1. Field of the Invention
The present invention relates generally to an air filtration system and, more particularly, relates to an air-filtration system to be worn over a user's head that filters air moving in and out of the air-filtration system.
2. Background of the Invention
Many personal air-filtration devices have been proposed by the prior art. Most of these devices include a helmet and a complicated air-filtering and circulating system. The manufacturing costs of most of these systems is high. Prior art air-filtration systems which are heavy or cumbersome significantly reduce the performance of the user. For example, a physician may experience an attenuated range of vision or an attenuated range of motion from helmets with small viewing windows or bulky designs. The weight of the helmet for a personal air-filtration system must be as low as possible to reduce fatigue and stress associated with a lengthy surgical procedure being performed by a physician. Even technicians in semi-conductor chip manufacturing clean rooms, for example, need personal air-filtration systems which are not heavy, complex, limiting in motion or vision, and which are affordable. An effective design which does not reduce the user's performance is needed.
U.S. Pat. No. 5,054,480 to Bare et al., issued on Oct. 8, 1991, discloses an air flow filtration control system to be worn by a user when a controlled air flow and air-filtration environment is required or desired. The personal air-filtration system includes a system of air passages for circulating air. At least one intake fan is located near the top of the helmet, and an exhaust fan is located near the bottom rear of the helmet. The majority of air is moved only through the air passages, and specific filters are placed over each of the intake and exhaust fans. The helmet of this system is cumbersome, complicated, and is also heavy due to the large number of individual air passages and fans.
Another helmet air-filtration system is disclosed in U.S. Pat. No. 4,901,716 to Stackhouse et al., issued on Feb. 20, 1990. This system is designed for use in a clean room, and pulls outside air into the helmet for filtration. The air entering the helmet is not filtered, but a number of flapper valves prevent contaminants from the wearer and this unfiltered air from leaving the helmet. Air is filtered as it is exhausted out of the helmet through powered filter systems. Such a system could not provide protection to a physician, since air entering the system is not filtered.
U.S. Pat. No. 3,525,334 to Braman et al. discloses a garment assembly to prevent personnel contamination from entering a working environment. The garment assembly includes a helmet, jacket and pants, and is described as being suited for use in clean rooms and similar low contamination areas.
A helmet-mounted air conditioning system is described in U.S. Pat. No. 5,193,347 to Apisdorf. This apparatus includes a heat absorption side and a heat dissipation side, but does not filter air entering the helmet or exiting the helmet. None of these prior art air filtration systems provide a comfortable, lightweight air-filtering system of simple and economical design. Nor do any of the prior art systems provide a vent hole located near the top the helmet for allowing warm air from the user's head, breath, or the fan mechanisms, for example, to escape therethrough.